Related papers: Extremely long baseline interferometry with Origin…
I review the astrophysical insights arising from high-precision astrometric observations of X-ray binary systems, focussing primarily (but not exclusively) on recent results with very long baseline interferometry. Accurate,…
Modern radio astrometry has reached the limit of the resolution that is determined by the size of the Earth. The only way to overcome that limit is to create the radio telescopes outside our planet. It is proposed to build an autonomous…
Despite numerous search campaigns based on a diverse set of observational techniques, exomoons - prospective satellites of extrasolar planets - remain an elusive and hard-to-pin-down class of objects. Yet, the case for intensifying this…
Radio observations using the Very Long Baseline Interferometry (VLBI) technique typically have fields of view of only a few arcseconds, due to the computational problems inherent in imaging larger fields. Furthermore, sensitivity…
A nearby primordial-black-hole (PBH) evaporation burst would produce a curved gamma-ray wavefront, leading to detectable departures from plane-wave inter-satellite delays. We introduce a purely geometric method that combines imaging…
This Special Issue of the Astrophysical Journal Letters is dedicated to presenting initial results from the Great Observatories Origins Deep Survey (GOODS) that are primarily, but not exclusively, based on multi--band imaging data obtained…
Primordial black holes possibly formed in the early universe could provide a significant fraction of the dark matter and would be unique probes of inflation. A smoking gun for their discovery would be the detection of a subsolar mass…
Dual active galactic nuclei (DAGN) and supermassive black hole binaries (SMBHBs) at kpc and pc-scale separations, respectively, are expected during stages of galaxy merger and evolution. Their observational identification can address a…
Ultraluminous X-ray sources (ULXs) are amongst the most intriguing of X-ray source classes. Their extreme luminosities - greater than 10^39 erg/s in the 0.3 - 10 keV band alone - suggest either the presence of black holes larger than those…
We have used VSOP space very long baseline interferometry observations to measure the brightness temperature distribution of a well-defined sub-set of the Pearson-Readhead sample of extragalactic radio sources. VLBI which is restricted to…
The extreme-mass-ratio inspirals (EMRIs) of stellar mass compact objects into massive black holes in the centres of galaxies are an important source of low-frequency gravitational waves for space-based detectors. We discuss the prospects…
The AuScope geodetic Very Long Baseline Interferometry array consists of three new 12 m radio telescopes and a correlation facility in Australia. The telescopes at Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western…
The LIGO discoveries have rekindled suggestions that primordial black holes (BHs) may constitute part to all of the dark matter (DM) in the Universe. Such suggestions came from 1) the observed merger rate of the BHs, 2) their unusual…
The evolving Laser Interferometer Space Antenna (eLISA) will revolutionize our understanding of the formation and evolution of massive black holes along cosmic history by probing massive black hole binaries in the $10^3-10^7$ solar mass…
Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event…
The Event Horizon Telescope has produced resolved images of the supermassive black holes Sgr A* and M87*, which present the largest shadows on the sky. In the next decade, technological improvements and extensions to the array will enable…
We show how an idealized high-frequency VLBI can probe the metric of nearby supermassive black holes. No quantitative assumptions about plasma dynamics are used in the suggested diagnostic, which is based on strong-field lensing.
Ground-based telescopes have been playing a leading role in exoplanet direct imaging science and technological development for the past two decades and will continue to have an indispensable role for the next decade and beyond. Extreme…
The Large Binocular Telescope Interferometer (LBTI) is a strategic instrument of the LBT designed for high-sensitivity, high-contrast, and high-resolution infrared (1.5-13 $\mu$m) imaging of nearby planetary systems. To carry out a wide…
Imaging the vicinity of a black hole is one of the ultimate goals of VLBI astronomy. The closest massive black hole, Sgr A*, located at the Galactic center, is the leading candidate for such observations. Combined with recent VLBI recording…